Display device

ABSTRACT

According to one embodiment, a display device includes a switching element, a common electrode, an insulating film covering the common electrode, a first pixel electrode electrically connected to the switching element in a first contact hole penetrating the insulating film, and a transparent conductive film electrically connected to the common electrode in a second contact hole penetrating the insulating film. The first pixel electrode and the transparent conductive film are arranged in a first direction in a same layer. A size of the first contact hole and a size of the second contact hole are different from each other in planar view.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of PCT Application No.PCT/JP2018/047600, filed Dec. 25, 2018 and based upon and claiming thebenefit of priority from Japanese Patent Application No. 2018-037619,filed Mar. 2, 2018, the entire contents of all of which are incorporatedherein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, various technologies for improving the display quality of adisplay device have been considered. For example, a technology forachieving uniform dimensional accuracy in pixel electrodes formed bypatterning a conductive film by disposing dummy pixel electrodes in thesame layer as the pixel electrodes on the outer side of a displayportion has been disposed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing the external appearance of a displaydevice DSP of the present embodiment.

FIG. 2 is a plan view showing a configuration example of a touch sensorTS.

FIG. 3 is a plan view showing a sensor electrode Rx shown in FIG. 2 andpixels PX.

FIG. 4 is an illustration showing the basic configuration and equivalentcircuit of the pixel PX.

FIG. 5A is an enlarged plan view of an area AR1 close to a straightportion E14 shown in FIG. 1.

FIG. 5B is another enlarged plan view of the area AR1 close to thestraight portion E14 shown in FIG. 1.

FIG. 6 is an enlarged plan view showing a pixel electrode PE11 and awire electrode EL11 shown in FIG. 5B.

FIG. 7 is a cross-sectional view of a first substrate SUB1 taken alongline A-B shown in FIG. 6.

FIG. 8A is a plan view showing a state where the wire electrode EL11 anda contact hole CH11 overlap.

FIG. 8B is another plan view showing a state where the wire electrodeEL11 and the contact hole CH11 overlap.

FIG. 9 is a cross-sectional view of a display panel PNL taken along lineC-D shown in FIG. 5B.

FIG. 10 is a plan view showing a configuration example of an area AR2close to a round portion R12 shown in FIG. 1.

FIG. 11 is a plan view showing another configuration example of the areaAR2 close to the round portion R12 shown in FIG. 1.

FIG. 12 is a plan view showing another configuration of the area AR2close to the round portion R12 shown in FIG. 1.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a displaydevice including a switching element, a common electrode, an insulatingfilm covering the common electrode, a first pixel electrode electricallyconnected to the switching element in a first contact hole penetratingthe insulating film, and a transparent conductive film electricallyconnected to the common electrode in a second contact hole penetratingthe insulating film. The first pixel electrode and the transparentconductive film are arranged in a first direction in a same layer. Thefirst pixel electrode is opposed to the common electrode in a displayportion displaying an image. The transparent conductive film is opposedto the common electrode in a non-display portion surrounding the displayportion. The common electrode is disposed over the display portion andthe non-display portion. A size of the first contact hole and a size ofthe second contact hole are different from each other in planar view.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is merely an example, and properchanges in keeping with the spirit of the invention, which are easilyconceivable by a person of ordinary skill in the art, come within thescope of the invention as a matter of course. In addition, in somecases, in order to make the description clearer, the widths,thicknesses, shapes, and the like of the respective parts areillustrated schematically in the drawings, rather than as an accuraterepresentation of what is implemented, but such schematic illustrationis merely exemplary, and in no way restricts the interpretation of theinvention. In addition, in the specification and drawings, constituentelements which function in the same or a similar manner to thosedescribed in connection with preceding drawings are denoted by the samereference numbers, and detailed explanations of them that are consideredredundant may be appropriately omitted.

In the present embodiment, a liquid crystal display device is explainedas an example of a display device DSP. The main configuration disclosedin the present embodiment can be applied to a self-luminous displaydevice including an organic electroluminescent display element or thelike, an electronic paper display device including an electrophoreticelement or the like, a display device employing micro-electromechanicalsystems (MEMS), a display device employing electrochromism, and thelike.

FIG. 1 is a plan view showing the external appearance of the displaydevice DSP of the present embodiment. A first direction X, a seconddirection Y and a third direction Z are, for example, orthogonal to oneanother but may cross at an angle other than 90 degrees. The firstdirection X and the second direction Y correspond to directions parallelto the main surface of a substrate constituting the display device DSP,and the third direction Z corresponds to the thickness direction of thedisplay device DSP. In the present specification, a position on thepointing end side of an arrow indicating the third direction Z isreferred to as above, and a position on a side opposite to the pointingend of the arrow is referred to as below. In addition, an observationposition at which the display device DSP is observed is assumed to belocated on the pointing end side of the arrow indicating the thirddirection Z, and viewing from this observation position toward an X-Yplane defined by the first direction X and the second direction Y isreferred to as planar view.

A plan view of the display device DSP in the X-Y plane is shown here.The display device DSP includes a display panel PNL, a flexible printedcircuit board 1 and an IC chip 2.

The display panel PNL is a liquid crystal display panel, and includes afirst substrate SUB1, a second substrate SUB2, a liquid crystal layer LCwhich will be described later, a sealant SE and a light-shielding layerLS. The display panel PNL includes a display portion DA which displaysan image, and a frame-shaped non-display portion NDA which surrounds thedisplay portion DA. The second substrate SUB2 is opposed to the firstsubstrate SUB1 in the third direction Z. The first substrate SUB1 has amounting portion MA extending in the second direction Y more than thesecond substrate SUB2.

The sealant SE is located in the non-display portion NDA, bonds thefirst substrate SUB1 and the second substrate SUB2 together, and sealsin the liquid crystal layer LC. The light-shielding layer LS is locatedin the non-display portion NDA. The sealant SE is disposed at a positionoverlapping the light-shielding layer LS in planar view. In FIG. 1, anarea where the sealant SE is disposed and an area where thelight-shielding layer LS is disposed are shown by different hatch lines,and an area where the sealant SE and the light-shielding layer LSoverlap is shown by crosshatching. The light-shielding layer LS isdisposed in the second substrate SUB2.

The display portion DA is located on an inner side surrounded by thelight-shielding layer LS. The display portion DA includes a plurality ofpixels PX arranged in a matrix in the first direction X and the seconddirection Y. The display portion DA has a pair of edge portions E1 andE2 extending along the first direction X, a pair of edge portions E3 andE4 extending along the second direction Y, and four round portions R1 toR4. The display panel PNL has a pair of straight portions E11 and E12extending along the first direction X, a pair of straight portions E13and E14 extending along the second direction Y, and two round portionsR11 and R12. The round portions R11 and R12 are located on the outersides of the round portions R1 and R2, respectively. The radius ofcurvature of the round portion R11 may be the same as or different fromthe radius of curvature of the round portion R1.

The flexible printed circuit board 1 and the IC chip 2 are mounted onthe mounting portion MA. Note that the IC chip 2 may be mounted on theflexible printed circuit board 1. The IC chip 2 includes a built-indisplay driver DD which outputs a signal required for displaying animage in a display mode of displaying an image. In the illustratedexample, the IC chip 2 includes a built-in touch controller TC whichcontrols a touch sensing mode of detecting approach or contact of anobject to or with the display device DSP.

The display panel PNL of the present embodiment may be a transmissivetype having a transmissive display function of displaying an image byselectively transmitting light from the rear surface side of the firstsubstrate SUB1, a reflective type having a reflective display functionof displaying an image by selectively reflecting light from the frontsurface side of the second substrate SUB2, or a transflective typehaving the transmissive display function and the reflective displayfunction.

In addition, although the explanation of the detailed configuration ofthe display panel PNL is omitted here, the display panel PNL may have aconfiguration conforming to any one of a display mode using a lateralelectric field along a substrate main surface, a display mode using alongitudinal electric field along a normal to a substrate main surface,a display mode using an inclined electric field inclined in an directioninclined with respect to a substrate main surface, and an appropriatecombination of the lateral electric field, the longitudinal electricfield and the inclined electric field. The substrate main surface hereis a surface parallel to the X-Y plane defined by the first direction Xand the second direction Y.

FIG. 2 is a plan view showing a configuration example of a touch sensorTS. Although the touch sensor TS of a self-capacitance method isexplained here, the touch sensor TS may be of a mutual-capacitancemethod. The touch sensor TS includes a plurality of sensor electrodes Rx(Rx1, Rx2, etc.) and a plurality of sensor lines L (L1, L2, etc.). Thesensor electrodes Rx are located in the display portion DA and arearranged in a matrix in the first direction X and the second directionY. One sensor electrode Rx constitutes a sensor block which is thesmallest unit which can perform touch sensing. The sensor lines L extendalong the second direction Y and are arranged in the first direction Xin the display portion DA. Each sensor line L is disposed at, forexample, a position overlapping a signal line S which will be describedlater. In addition, each sensor line L is drawn to the non-displayportion NDA and is electrically connected to the IC chip 2.

Here, attention will be focused on the relationship between the sensorlines L1 to L3 arranged in the first direction X and the sensorelectrodes Rx1 to Rx3 arranged in the second direction Y. The sensorline L1 overlaps the sensor electrodes Rx1 to Rx3 and is electricallyconnected to the sensor electrode Rx1. The sensor line L2 overlaps thesensor electrodes Rx2 and Rx3 and is electrically connected to thesensor electrode Rx2. A dummy line D20 is apart from the sensor line L2.The dummy line D20 overlaps the sensor electrode Rx1 and is electricallyconnected to the sensor electrode Rx1. The sensor line L2 and the dummyline D20 are located on the same signal line. The sensor line L3overlaps the sensor electrode Rx3 and is electrically connected to thesensor electrode Rx3. A dummy line D31 overlaps the sensor electrode Rx1and is electrically connected to the sensor electrode Rx1. A dummy lineD32 is apart from the dummy line D31 and the sensor line L3. The dummyline D32 overlaps the sensor electrode Rx2 and is electrically connectedto the sensor electrode Rx2. The sensor line L3 and the dummy lines D31and D32 are located on the same signal line.

In the touch sensing mode, the touch controller TC applies a touch drivevoltage to the sensor lines L. Accordingly, the touch drive voltage isapplied to the sensor electrodes Rx, and sensing is performed in thesensor electrodes Rx. Sensor signals corresponding to the sensingresults in the sensor electrodes Rx are output to the touch controllerTC via the sensor lines L. The touch controller TC or an external hostdetects the presence or absence of the approach or contact of an objectto or with the display device DSP and the coordinates of the position ofan object based on the sensor signals.

Note that, in the display mode, the sensor electrodes Rx function ascommon electrodes CE to which a common voltage (Vcom) is applied. Thecommon voltage is a voltage different from the touch drive voltage, andis applied from, for example, a voltage supply unit included in thedisplay driver DD via the sensor lines L.

In the non-display portion NDA, the wiring lines WL1 to WL3 aredisposed. In the illustrated example, the wiring lines WL1 to WL3 aredisposed along the straight portion E13, the round portion R11, thestraight line E11, the round portion R12 and the straight line E14. Thewiring line WL2 is the closest of the wiring lines WL1 to WL3 to thedisplay portion DA. The wiring line WL1 is located between the wiringline WL2 and the wiring line WL3. For example, the potential of thewiring line WL1 is a fixed potential different from the potentials ofthe wiring lines WL2 and WL3. In addition, the potential of the wiringline WL2 is the same as the potential of the wiring line WL3. Forexample, the common voltage is applied to the wiring line WL2 and thewiring line WL3. The potential of the wiring line WL1 may be relativelylower or higher than the potential of the wiring line WL2. In a casewhere the potential of the wiring line WL1 is lower than the potentialof the wiring line WL2, the wiring line WL1 functions as an ion trapline which traps impurity ions having positive polarity. Alternatively,in a case where the potential of the wiring line WL1 is higher than thepotential of the wiring line WL2, the wiring line WL1 functions as anion trap line which traps impurity ions having negative polarity.

FIG. 3 is a plan view showing the sensor electrode Rx shown in FIG. 2and pixels PX. In FIG. 3, a direction crossing at an acute anglecounterclockwise with respect to the second direction Y is define as adirection D1, and a direction crossing at an acute angle clockwise withrespect to the second direction Y is defined as a direction D2. Notethat an angle θ1 formed by the second direction Y and the direction D1is substantially the same as an angle θ2 formed by the second directionY and the direction D2.

One sensor electrode Rx is arranged over a plurality of pixels PX. Inthe illustrated example, the pixels PX located in odd-numbered rowsalong the second direction Y extend along the direction D1. In addition,the pixels PX located in even-numbered rows along the second direction Yextend along the direction D2. Note that the pixel PX here indicates thesmallest unit which can be individually controlled according to a pixelsignal and is referred to also as a sub-pixel. In addition, the smallestunit which realizes color display may be referred to as a main pixel MP.The main pixel MP is composed of a plurality of sub-pixels PX whichdisplay different colors. For example, the main pixel MP includes a redpixel which displays red, a green pixel which displays green and a bluepixel which displays blue as sub-pixels PX. In addition, the main pixelMP may include a white pixel which displays white.

For example, in one sensor electrode Rx, 60 to 70 main pixels MP arearranged along the first direction X, and 60 to 70 main pixels MP arearranged along the second direction Y.

FIG. 4 is an illustration showing the basic configuration and equivalentcircuit of the pixel PX. A plurality of scanning lines G are connectedto a scanning line drive circuit GD. A plurality of signal lines S areconnected to a signal line drive circuit SD. Note that the scanninglines G and the signal lines S do not necessarily linearly extend butmay be partly bent. For example, even if the signal lines S are partlybent, the signal lines S are assumed to extend in the second directionY.

A common electrode CE is disposed in each sensor block B. Each commonelectrode CE is connected to a voltage supply unit CD of the commonvoltage (Vcom) and is arranged over a plurality of pixels PX. Inaddition, each common electrode CE is connected to the touch controllerTC and functions as the sensor electrode Rx as described above.

Each pixel PX includes a switching element SW, a pixel electrode PE, thecommon electrode CE, a liquid crystal layer LC and the like. Theswitching element SW is composed of, for example, a thin-film transistor(TFT) and is electrically connected to the scanning line G and thesignal line S. The scanning line G is electrically connected to a gateelectrode GE of the switching element SW in each of the pixels PXarranged in the first direction X. The signal line S is electricallyconnected to a source electrode SE of the switching element SW in eachof the pixels PX arranged in the second direction Y. The pixel electrodePE is electrically connected to a drain electrode DE of the switchingelement SW. Each pixel electrode PE is opposed to the common electrodeCE and drives the liquid crystal layer LC by an electric field generatedbetween the pixel electrode PE and the common electrode CE. A storagecapacitance CS is formed between, for example, an electrode having thesame potential as the common electrode CE and an electrode having thesame potential as the pixel electrode PE.

FIGS. 5A and 5B are enlarged views of an area AR1 close to the straightportion E14 shown in FIG. 1. The respective layers of a semiconductorlayer SC, the scanning line G and the signal line S included in thefirst substrate SUB1 are illustrated in FIG. 5A, and the respectivelayers of the scanning line G, the signal line S and the pixel electrodePE are illustrated in FIG. 5B. Note that the layer of the commonelectrode CE is shown by a dotted line. The illustration of theconfiguration between the wiring line WL2 and the straight portion E13is omitted.

As shown in FIG. 5A, the scanning lines G11 to G13 linearly extend alongthe first direction X and are arranged at intervals in the seconddirection Y. The signal lines S11 to S14 extend along substantially thesecond direction Y and are arranged at intervals in the first directionX. The scanning lines G11 to G13 and the signal lines S11 to S14 crosseach other. The common electrode CE is disposed over the display portionDA and the non-display portion NDA.

In the display portion DA, each of the scanning lines G11 to G13 and aplurality of semiconductor layers SC cross each other. In addition, eachof the signal lines S11 to S14 is electrically connected to a pluralityof semiconductor layers SC. Pixels PXE1 to PXE3 located between thesignal lines S13 and S14 correspond to the outermost pixels in thedisplay portion DA. That is, the pixels PXE1 to PXE3 are the closestpixels to the non-display portion NDA or the closest pixels to thestraight portion E14. For example, a semiconductor layer SC11 in thepixel PXE1 crosses the scanning line G11 at two positions, and iselectrically connected to the signal line S14 in a contact hole CH1.

In the non-display portion NDA, each of the scanning lines G11 to G13and a plurality of dummy semiconductor layers DSC cross each other. Eachdummy semiconductor layer DSC is not electrically connected to any ofthe signal lines S11 to S14 and is electrically floating. The dummysemiconductor layers DSC adjacent to the display portion DA overlap thecommon electrode CE. The dummy semiconductor layers DSC apart from thedisplay portion DA overlap the wiring line WL2 having a fixed potential.

The wiring line WL2 is apart from the common electrode CE. The wiringline WL2 includes a first layer WL21 and a second layer WL22. The firstlayer WL21 is a metal layer located in the same layer as the signal lineS and formed of the same material as the signal line S. The second layerWL22 is a transparent conductive layer located in the same layer as thecommon electrode CE and formed of the same material as the commonelectrode CE, and is overlaid on the first layer WL21. Note that aninsulating film is interposed between the first layer WL21 and thesecond layer WL22.

As shown in FIG. 5B, the pixel electrodes PE are arranged in a matrix inthe first direction X and the second direction Y in the display portionDA. In addition, each pixel electrode PE is opposed to the commonelectrode CE in the display portion DA. For example, a pixel electrodePE1 located between the scanning lines G11 and G12 includes a pluralityof strip electrodes Pa1 extending along the direction D1. In addition, apixel electrode PE2 located between the scanning lines G12 and G13includes a plurality of strip electrodes Pa2 extending along thedirection D2. The number of strip electrodes Pa1 and the number of stripelectrodes Pa2 are two in the illustrated example but may be greaterthan or equal to three. In addition, the number of strip electrodes Pa1may be different from the number of strip electrodes Pa2.

A pixel electrode PE11 of the pixel PXE1 is electrically connected tothe semiconductor layer SC11 shown in FIG. 5A. A pixel electrode PE12 ofthe pixel PXE2 has the same shape as the pixel electrode PE1. The pixelelectrode PE11 and a pixel electrode PE13 of the pixel PXE3 have thesame shape as the pixel electrode PE2.

Wire electrodes EL11 and EL13 are located in the non-display portionNDA. Both of the wire electrodes EL11 and EL13 are transparentconductive films (or transparent electrodes) located in the same layeras the pixel electrode PE and formed of the same material as the pixelelectrode PE. The wire electrodes EL11 and EL13 are opposed to thecommon electrode CE in the non-display portion NDA. The pixel electrodePE11 and the wire electrode EL11 are arranged in the first direction X.In addition, the pixel electrode PE12 and the wire electrode EL13 arearranged in the first direction X, and the pixel electrode PE13 and thewire electrode EL13 are arranged in the first direction X. The signalline S14 is located between the pixel electrode PE11 and the wireelectrode EL11 and between the pixel electrode PE12 and the wireelectrode EL13.

The wire electrode EL13 will be more specifically explained. The wireelectrode EL13 crosses the scanning line G12 and is adjacent to twopixels PXE2 and PXE3 arranged in the second direction Y. The wireelectrode EL13 includes an electrode portion 131 extending along thedirection D1, an electrode portion 132 extending along the direction D2,and a base portion 133. The pixel electrode PE12 and the electrodeportion 131 are arranged in the first direction X, and the pixelelectrode PE13 and the electrode portion 132 are arranged in the firstdirection X. The base portion 133 is located close to a portion in whichthe scanning line G13 and the signal line S14 cross each other, and iselectrically connected to the common electrode CE in a contact holeCHl3.

The wiring line WL2 further includes a third layer WL23. The third layerWL23 is a transparent conductive layer located in the same layer as thepixel electrode PE11, the wire electrode EL11 and the like and formed ofthe same material as the pixel electrode PE.

In the example shown in FIG. 5B, the pixel electrode PE11 corresponds tothe first pixel electrode. Alternatively, the pixel electrode PE12corresponds to the first pixel electrode, and the pixel electrode PE13corresponds to the second pixel electrode.

FIG. 6 is an enlarged plan view showing the pixel electrode PE11 and thewire electrode EL11 shown in FIG. 5B.

The switching element SW is electrically connected to the scanning lineG11 and the signal line S14. The switching element SW in the illustratedexample has a double-gate structure. The switching element SW includesthe semiconductor layer SC11 and a drain electrode DE11. Note that thedrain electrode DE11 may be referred to as a source electrode in theswitching element SW. The semiconductor layer SC11 overlaps the signalline S14 in one portion, extends between the signal lines S13 and S14 inthe other portion, and is formed in a substantially U shape. Thesemiconductor layer SC11 crosses the scanning line G11 in an areaoverlapping the signal line S14 and in an area between the signal linesS13 and S14. In the scanning line G11, the areas overlapping thesemiconductor layer SC11 function as gate electrodes GE. The signal lineS14 is electrically connected to one end portion SCA of thesemiconductor layer SC11 in the contact hole CH1. The drain electrodeDE11 is formed in the shape of an island and is disposed between thesignal lines S13 and S14. The drain electrode DE11 is electricallyconnected to the other end portion SCB of the semiconductor layer SC11in the contact hole CH2.

The pixel electrode PE11 includes a base portion BS which is integrallyformed with the strip electrodes Pa2. The base portion BS overlaps thedrain electrode DE11. The base portion BS is electrically connected tothe drain electrode DE11. In the illustrated example, a structure ofconnection between the drain electrode DE11 and the pixel electrode PE11will be briefly explained. A connection electrode RE11 is disposedbetween the drain electrode DE11 and the base portion BS. The connectionelectrode RE11 is a transparent electrode formed of the same material asthe common electrode CE and is formed in the same process as the commonelectrode CE. The connection electrode RE11 is electrically connected tothe drain electrode DE11 in the contact hole CH3. The base portion BS iselectrically connected to the connection electrode RE11 in a contacthole CH10.

The wire electrode EL11 includes an electrode portion 112 and a baseportion 113. The base portion 113 is electrically connected to thecommon electrode CE in a contact hole CH11. The base portion 113overlaps the entire contact hole CH11 in planar view. The contact holeCH11 here is a hole penetrating an insulating film interposed betweenthe common electrode CE and the base portion 113, and indicates theboundary between the insulating film and the common electrode CE inplanar view. That is, the base portion 113 covers the entire commonelectrode CE exposed from the contact hole CH11.

Attention will be focused on the pixel electrode PE11 and the wireelectrode EL11. When a width W11 of the strip electrode Pa2 and a widthW12 of the electrode portion 112 are compared with each other, the widthW12 is greater than the width W11. Note that the widths W11 and W12 hereare lengths along the first direction X.

The electrode portion 112 extends in a direction parallel to the stripelectrode Pa2. In the illustrated example, both the strip electrode Pa2and the electrode portion 112 extend along the direction D2.

A distance D11 between the strip electrode Pa2 and the signal line S14is equal to a distance D12 between the electrode portion 112 and thesignal line S14. The distances D11 and D12 are lengths along the firstdirection X.

The size of the contact hole CH10 is different from the size of thecontact hole CH11. In the illustrated example, the size of the contacthole CH11 is greater than the size of the contact hole CH10 in planarview. Note that the size of the contact hole CH10 can be defined as, forexample, the area of the connection electrode RE11 in the contact holeCH10, and similarly, the size of the contact hole CH11 can be defined asthe area of the common electrode CE in the contact hole CH11.

One dummy semiconductor layer DSC overlaps the wire electrode EL11.

In the example shown in FIG. 6, the pixel electrode PE11 corresponds tothe first pixel electrode, the contact hole CH10 corresponds to thefirst contact hole, and the contact hole CH11 corresponds to the secondcontact hole.

FIG. 7 is a cross-sectional view of the first substrate SUB1 taken alongline A-B shown in FIG. 6. The illustrated example corresponds to a casewhere a fringe field switching (FFS) mode which is a display mode usinga lateral electric field is applied.

The first substrate SUB1 includes an insulating substrate 10, insulatingfilms 11 to 15, the semiconductor layer SC11, the dummy semiconductorlayer DSC, the drain electrode DE11, the signal line S14, the connectionelectrode RE11, the common electrode CE, the pixel electrode PE11, thewire electrode EL11, an alignment film AL1 and the like.

The insulating substrate 10 is a substrate having optical transparencysuch as a glass substrate or a flexible resin substrate. The insulatingfilm 11 is located on the insulating substrate 10. The semiconductorlayer SC11 is located on the insulating film 11 and is covered with theinsulating film 12. The drain electrode DE11 and the signal line S14 arelocated on the insulating film 13 and are covered with the insulatingfilm 14. The connection electrode RE11 and the common electrode CE arelocated on the insulating film 14 and are covered with the insulatingfilm 15. The connection electrode RE11 is in contact with the drainelectrode DE11 in the contact hole CH3 penetrating the insulating film14. The illustrated common electrode CE is located on a flat uppersurface 14A of the insulating film 14 and does not overlap any of thecontact holes in the insulating films 11 to 14. The pixel electrode PE11and the wire electrode EL11 are located on the insulating film 15 andare covered with the alignment film AL1. The base portion BS of thepixel electrode PE11 is in contact with the connection electrode RE11 inthe contact hole CH10 penetrating the insulating film 15. The baseportion 113 of the wire electrode EL11 is in contact with the commonelectrode CE in the contact hole CH11 penetrating the insulating film15. The alignment film AL1 is not in contact with the common electrodeCE but is directly stacked on the wire electrode EL11 in the contacthole CH11. Directly below the contact hole CH11, the insulating film 14is directly stacked on the insulating film 13, and no conductive layeris disposed in the same layer as the signal line S14. That is, betweenthe dummy semiconductor layer DSC and the common electrode CE, theinsulating film 13 is directly stacked on the insulating film 12, theinsulating film 14 is directly stacked on the insulating film 13, andthe common electrode CE is not in contact with the dummy semiconductorlayer DSC. Directly above the signal line S14, the insulating film 15 isdirectly stacked on the insulating film 14.

Each of the signal line S14 and the drain electrode DE11 is formed of ametal material such as aluminum (Al), titanium (Ti), silver (Ag),molybdenum (Mo), tungsten (W), copper (Cu) or chromium (Cr), an alloyobtained by combining these metal materials or the like, and may have asingle-layer structure or a multilayer structure. Each of the connectionelectrode RE11, the common electrode CE, the pixel electrode PE11 andthe wire electrode EL11 is a transparent electrode formed of atransparent conductive material such as indium tin oxide (ITO) or indiumzinc oxide (IZO).

Each of the insulating films 11 to 13 and the insulating film 15 is aninorganic insulating film formed of an inorganic insulating materialsuch as silicon oxide, silicon nitride or silicon oxynitride, and mayhave a single-layer structure or a multilayer structure. The insulatingfilm 14 is, for example, an organic insulating film formed of an organicinsulating material such as acrylic resin.

As described above, the contact hole CH11 is larger than the contacthole CH10. This is caused by a difference in underlying structurebetween the contact holes CH10 and CH11. That is, since the contact holeCH10 partly overlaps the contact hole CH3, the contact hole CH10 isinfluenced by a difference in level of the insulating film 14. On theother hand, the contact hole CH11 overlaps the flat upper surface 14A.Therefore, at the time of etching the insulating film 14, a differencein etching conditions between the areas corresponding to the contactholes CH10 and CH11 causes a difference in size between the contactholes CH10 and CH11.

In the present embodiment, even if the contact hole CH11 is expanded,the common electrode CE exposed from the contact hole CH11 is stillentirely covered with the wire electrode EL11. Therefore, moistureintrusion from the contact hole CH11 can be suppressed.

Moisture intrusion from the contact hole CH11 may cause, for example,the common electrode CE and the insulating film 15 to peel away fromeach other. In the pixel PX of the display portion DA, if the commonelectrode CE and the insulating film 15 are peeled away from each other,a voltage applied to liquid crystal cannot be held between the pixelelectrode PE and the common electrode CE, and display failure occurs(black display irregularities appear).

The inventors prepared the first sample in which the entire contact holeCH11 is covered with the wire electrode and the second sample in which apart of the contact hole CH11 is covered with the wire electrode, andconducted an experiment by exposing them to environment of hightemperature and high humidity. As the experiment conditions, thetemperature was 85° C., the humidity was 85%, and the amount of time forexposure was 240 hours. As a result of the experiment, black displayirregularities appeared in the second sample but black displayirregularities did not appear in the first sample. The experimentconfirmed that covering of the entire contact hole CH11 with the wireelectrode is effective in suppressing black display irregularitiescaused by moisture intrusion.

Therefore, according to the present embodiment, degradation in displayquality can be suppressed.

FIGS. 8A and 8B are plan views showing a state where the wire electrodeEL11 overlaps the entire contact hole CH11. In each of the illustratedconfiguration examples, both an edge 113E of the base portion 113 and anedge CHE of the contact hole CH11 are formed in a rectangular shape, butare not limited to this shape, and may be formed in another shape suchas a circular shape or an elliptical shape.

In the configuration example shown in FIG. 8A, one end portion 113A ofthe base portion 113 has a width W21, and the other end portion 113B ofthe base portion 113 has a width W22. The widths W21 and W22 are lengthsalong the second direction Y. The width W21 is equal to the width W22.The contact hole CH11 is located between one end portion 113A and theother end portion 113B. The entire edge CHE overlaps the base portion113. That is, in planar view, the edge 113E does not cross the edge CHE,and the entire edge 113E is located more outward than the edge CHE. Ashortest distance L between the edge 113E and the edge CHE is greaterthan or equal to 1 μm, preferably, greater than or equal to 2 μm, morepreferably, greater than or equal to 2.25 μm.

The configuration example shown in FIG. 8B is different from theconfiguration example shown in FIG. 8A in that the base portion 113 isexpanded. More specifically, the other end portion 113B is expandedalong the second direction Y more than one end portion 113A. The widthW22 is greater than the width W21. Therefore, as compared with theconfiguration example shown in FIG. 8A, the entire edge 113E is locatedeven more outward than the edge CHE, and the shortest distance L betweenthe edge 113E and the edge CHE are expanded. According to such aconfiguration example, even if the wire electrode EL11 and the contacthole CH11 are relatively displaced from each other, the entire contacthole CH11 is still covered with the wire electrode EL11, and moistureintrusion can still be suppressed.

FIG. 9 is a cross-sectional view of the display panel PNL taken alongline C-D shown in FIG. 5B. The configuration of the first substrate SUB1has been explained with reference to FIG. 7. Note that, althoughillustrations and explanations are omitted in FIG. 7, for example, theinsulating film 14 may be formed of a double-layer structure of aninsulating film 141 and an insulating film 142, and metal lines ML13 andML14 may be disposed between the insulating film 141 and the insulatingfilm 142. The metal line ML13 is located directly above the signal lineS13 and extends parallel to the signal line S13. The metal line ML14 islocated directly above the signal line S14 and extends parallel to thesignal line S14. These metal lines ML13 and ML14 can form the sensorlines L (L1, L2, L3, etc.) of the touch sensor TS or the dummy lines Dexplained with reference to FIG. 2. In this case, the common electrodeCE formed in the display portion DA is formed on the insulating film 142and is electrically connected to the sensor line L via a contact holeformed in the insulating film 142. The insulating film 141 is locatedbetween the insulating film 13 and the insulating film 142, covers theswitching element, and forms a flat upper surface (a surface which is incontact with the insulating film 142 or a surface which is in contactwith the sensor line L). The insulating film 141 is formed of an organicmaterial, and the insulating film 142 may be formed of the same organicmaterial as the insulating film 141 or be formed of an inorganicmaterial. Furthermore, a connection electrode formed of the samematerial and formed in the same process as the sensor line L may beformed between the connection electrode RE11 and the drain electrode DE.

The second substrate SUB2 includes an insulating substrate 20, alight-shielding layer BM, a color filter CF, an overcoat layer OC, analignment film AL2 and the like. Similarly to the insulating substrate10, the insulating substrate 20 is a substrate having opticaltransparency such as a glass substrate or a flexible resin substrate.The light-shielding layer BM and the color filter CF are located on aside opposed to the first substrate SUB1 of the insulating substrate 20.The color filter CF is opposed to the pixel electrode PE11 in the thirddirection Z. The overcoat layer OC covers the color filter CF. Theovercoat layer OC is formed of transparent resin. As the color filterCF, a red color filter, a green color filter, a blue color filter andthe like are included. The alignment film AL2 covers the overcoat layerOC. The alignment films AL1 and AL2 are formed of, for example, amaterial exhibiting horizontal alignment properties.

The first substrate SUB1 and the second substrate SUB2 described aboveare disposed such that the alignment films AL1 and AL2 are opposed toeach other. The cell gap between the first substrate SUB1 and the secondsubstrate SUB2 is, for example, 2 to 5 μm.

The liquid crystal layer LC is located between the first substrate SUB1and the second substrate SUB2 and is held between the alignment film AL1and the alignment film AL2. The liquid crystal layer LC contains liquidcrystal molecules LM. The liquid crystal layer LC is composed of apositive liquid crystal material (having positive dielectric anisotropy)or a negative liquid crystal material (having negative dielectricanisotropy).

An optical element OD1 including a polarizer PL1 is bonded to theinsulating substrate 10. An optical element OD2 including a polarizerPL2 is bonded to the insulating substrate 20. Note that each of theoptical elements OD1 and OD2 may include a retardation plate, ascattering layer, an antireflective layer or the like as needed. Anillumination device IL illuminates the first substrate SUB1 of thedisplay panel PNL with white illumination light.

In this display panel PNL, in an off state where an electric field isnot formed between the pixel electrode PE11 and the common electrode CE,the liquid crystal molecules LM are initially aligned in a predetermineddirection between the alignment films AL1 and AL2. In the off state, theillumination light emitted from the illumination device IL toward thedisplay panel PNL is absorbed in the optical elements OD1 and OD2, andthis results in dark display. On the other hand, in an on state where anelectric field is formed between the pixel electrode PE11 and the commonelectrode CE, the liquid crystal molecules LM are aligned in a directiondifferent from the initial alignment direction by the electric field,and the alignment direction is controlled by the electric field. In theon state, a part of the illumination light from the illumination deviceIL is transmitted through the optical elements OD1 and OD2, and thisresults in light display.

FIG. 10 is a plan view showing a configuration example of an area AR2close to the round portion R12 shown in FIG. 1.

As shown in the drawing, in the area AR2, the number of pixel electrodesPE arranged in the first direction X varies according to row. A row iscomposed of pixels arranged in the first direction X. In each row, thepixel electrode PEX in the outermost pixel and the wire electrode EL1are arranged in the first direction X. In the illustrated example, onewire electrode EL1 is disposed in each row, and one wire electrode EL1and one pixel electrode PEX are arranged in the first direction X.

Between the wire electrode EL1 and the wiring line WL2, an electrode EL2located in the same layer as the pixel electrode PEX and the wireelectrode EL1 is disposed. The electrode EL2 is electrically connectedto the common electrode CE in a plurality of contact holes CH20. Thatis, both the wire electrode EL1 and the electrode EL2 are electricallyconnected to the common electrode CE and have the same potential. Theelectrode EL2 is apart from not only the pixel electrode PEX but alsothe other pixel electrode PE, and is also apart from the wiring lineWL2. The electrode EL2 spreads over a space between each of the pixelelectrode PE and the wire electrode EL1 and the wiring line WL2.

For example, the electrode EL2 has a width W31 between a first portionELLA of the wire electrode EL1 and the wiring line WL2, and has a widthW32 between a second portion EL1B of the wire electrode EL1 and thewiring line WL2. The first portion EL1A is closer to the contact holeCH11 than the second portion EL1B. The width W31 is greater than thewidth W32. These widths W31 and W32 are lengths along the firstdirection X.

In addition, the electrode EL2 has a width W41 between the pixelelectrode PEX and the wiring line WL2, and has a width W42 between thewire electrode EL1 and the wiring line WL2. The width W41 is greaterthan the width W42. These widths W41 and W42 are lengths along thesecond direction Y.

The pixel electrode PE, the wire electrode EL1 and the electrode EL2 areformed by patterning the same transparent conductive film. According tothe present configuration example, at the time of patterning, it ispossible to suppress narrowing of the pixel electrode PEX of theoutermost pixel relative to the pixel electrode PE close to the centerof the display portion DA. Therefore, uniform dimensional accuracy canbe achieved in the pixel electrodes PE.

FIG. 11 is a plan view showing another configuration example of the areaAR2 close to the round portion R12 shown in FIG. 1.

The configuration example shown in FIG. 11 is different from theconfiguration example shown in FIG. 10 in that the wire electrode EL1 isomitted and the pixel electrode PEX and the electrode EL2 are arrangedin the first direction X. As described above, since the wire electrodeEL1 has the same potential as the electrode EL2, the wire electrode canbe omitted. Note that a distance D21 between the pixel electrode PEX andthe electrode EL2 is equal to a distance D22 between the pixel electrodePE and the pixel electrode PEX. These distances D21 and D22 are lengthsalong the first direction X.

In this configuration example also, substantially the same effects asthose of the configuration example shown in FIG. 10 can be obtained.

FIG. 12 is a plan view showing another configuration example of the areaAR2 close to the round portion R12 shown in FIG. 1.

The illustrated configuration example is different from theconfiguration example shown in FIG. 10 in that the electrode EL2 isomitted and the wire electrode EL1 is bent into a substantially L shape.That is, the wire electrode EL1 includes a first electrode portion 101and a second electrode portion 102 extending in a direction differentfrom the first electrode portion 101. The first electrode portion 101 iscloser to the contact hole CH11 than the second electrode portion 102.The first electrode portion 101 extends parallel to the pixel electrodePEX. The pixel electrode PEX and the first electrode portion 101 arearranged in the first direction X. The second electrode portion 102 iscontinuous with the first electrode portion 101. The second electrodeportion 102 extends along the first direction X. The second electrodeportion 102 and the pixel electrode PEX are arranged in the seconddirection Y. In addition, the second electrode portion 102 and the otherpixel electrode PE are arranged in the second direction Y.

In this configuration example also, substantially the same effects asthose of the configuration example shown in FIG. 10 can be obtained.

As explained above, according to the present embodiment, a displaydevice which can suppress degradation in display quality can beprovided.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

For example, the red pixel, the green pixel and the white pixel have thesame pixel width in the present embodiment but may have different pixelwidths from one another. In addition, the pixel electrodes of the redpixel, the green pixel and the white pixel have the same shape in thepresent embodiment but may have different shapes from one another.

What is claimed is:
 1. A display device comprising: a signal line; aswitching element; a common electrode; an insulating film covering thecommon electrode; a first pixel electrode electrically connected to theswitching element in a first contact hole penetrating the insulatingfilm; and a transparent conductive film electrically connected to thecommon electrode in a second contact hole penetrating the insulatingfilm, wherein the first pixel electrode and the transparent conductivefilm are arranged in a first direction in a same layer, the first pixelelectrode is opposed to the common electrode in a display portiondisplaying an image, the transparent conductive film is opposed to thecommon electrode in a non-display portion surrounding the displayportion, the common electrode is disposed over the display portion andthe non-display portion, a size of the first contact hole and a size ofthe second contact hole are different from each other in planar view,the first pixel electrode comprises a plurality of strip electrodes, thetransparent conductive film is a wire electrode, a width of the wireelectrode is greater than a width of the strip electrode, the signalline is located between the first pixel electrode and the wireelectrode, and a distance between the strip electrode and the signalline is equal to a distance between the wire electrode and the signalline.
 2. The display device of claim 1, wherein the wire electrodeextends in a direction parallel to the strip electrode.
 3. The displaydevice of claim 1, further comprising: a scanning line crossing thesignal line; a semiconductor layer of the switching element, thesemiconductor layer crossing the scanning line and electricallyconnected to the signal line and the first pixel electrode; and a dummysemiconductor layer crossing the scanning line, overlapping the wireelectrode, and being electrically floating.
 4. The display device ofclaim 1, wherein a distance between an edge of the second contact holeand an edge of the transparent conductive film is greater than or equalto 1 μm in planar view.
 5. A display device comprising: a switchingelement; a common electrode; an insulating film covering the commonelectrode; a first pixel electrode electrically connected to theswitching element in a first contact hole penetrating the insulatingfilm; a transparent conductive film electrically connected to the commonelectrode in a second contact hole penetrating the insulating film; aninorganic insulating film; a signal line and a drain electrode of theswitching element located on the inorganic insulating film; and anorganic insulating film covering the signal line and the drain electrodeand stacked on the inorganic insulating film, wherein the first pixelelectrode and the transparent conductive film are arranged in a firstdirection in a same layer, the first pixel electrode is opposed to thecommon electrode in a display portion displaying an image, thetransparent conductive film is opposed to the common electrode in anon-display portion surrounding the display portion, the commonelectrode is disposed over the display portion and the non-displayportion, a size of the first contact hole and a size of the secondcontact hole are different from each other in planar view, the commonelectrode is located on the organic insulating film, the first pixelelectrode is electrically connected to the drain electrode in a thirdcontact hole penetrating the organic insulating film, the drainelectrode and the first pixel electrode are connected to each other by aconnection electrode in the third contact hole and the first contacthole, and directly below the second contact hole, the organic insulatingfilm is stacked on the inorganic insulating film and no conductive layeris disposed in the same layer as the signal line.
 6. The display deviceof claim 5, further comprising a second pixel electrode, wherein thefirst pixel electrode and the second pixel electrode are arranged in asecond direction, and the second pixel electrode and the transparentconductive film are arranged in the first direction.
 7. The displaydevice of claim 5, further comprising: a wiring line having a fixedpotential and located in the non-display portion; and an electrodelocated in a same layer as the first pixel electrode and the transparentconductive film and electrically connected to the common electrode,wherein the electrode is apart from the first pixel electrode and thewiring line and spreads between the first pixel electrode and the wiringline.
 8. The display device of claim 5, wherein the transparentconductive film has a first electrode portion, and a second electrodeportion extending in a direction different from the first electrodeportion, the first pixel electrode and the first electrode portion arearranged in a first direction, and the first pixel electrode and thesecond electrode portion are arranged in a second direction.